Tuning device for pianos.



c. c. MEINZLT. TUNING DEVICE FOR PIANOS. APPLICATION FILED JULY 2l Patented Feb. 26, 1918.

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I 1 I I |I lxIII IIIIIIIIII L C C. MEINZOLT. TUNING DEVICE Foa Pumas. APPLICATION FILED IULY 2|. |914.

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C. C. MEINZOLT.

TumNG Device Fon PIANos.

APPLICATION FILED JULY 21,1914.

Patented Feb. 26,1918.

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CARL CHRISTIAN 1V.[EI1\TZ()L'I 7 OF PADDINGTON, NEW SOUTH WALES, AUSTRALIA.

TUNING DEVICE FOR PIANOS.

Application filed July 21, 1914.

De it lin/mn that l. (Tini. (."viinis'riax lflinN- Korir. .subject i the King ot Great Britain and lrr-la'rd ingrat Pei, Padding 'Xi-a' South i\nstralia, haw nwnteil new and n 'etal lniin 'o\'einents f Devices for l nies, oli which the e specil'ration.

:cation has been devised with a rien' to increase the t'nance and the Volinne et .sound in piaiwliortes and particularl \fY an upright piano. For this pini-pose inanji' small improvements have been niadc in ling dem of gnnfsirxnation of a. piano, but the inain tentures ot improvement are centered in the sonnd board and in an entirely new ineiliod ot' stringing a pianoforte, snch method ot sti-inging also atlording greater 'facilities lor tuning.

'ln order that the iin/cation may be properliY understood rehirenee will now be made to the a-ccoinpanying sheets ot drawings, in \\'hich:--

Figure 1 is a ilront ele\ ation et the nietal traine or string plate.

Fig. 9 a troni;'elevation oi the sound board, secured to the wooden 'traine at the back, with an edge View ot one of the fulllength ribs behind the sound board.

Fig. 3 is a rear elevation of the saine., with an edge rien' el the sound board and one ol' the ribs.

F l is a liront elevation olf the stringing appliances 'for the last live treble notes.

Fig. is a vertical section ot the saine on the line 5v5 oi Fi l. looking' in the direction of the arrow.

.Fi G is a front elevation ot the Stringing appliances for the nnicord and bicord notes in the bass.

Fig. T is a. vertical section of the saine taken on the line 7 7 of Fig. 6.

Fig. 8 is a perspective View of a. full tricord sot of strings in the treble.

Fig. 9 is a front elevation, showing' how the bach of the bass wrest plate is punched with holes.

Fig. 10 is a front elevation, showing how the back of the treble Wrest plate is punched with holes.

Fig. 11 shows in perspective, and isolated, the three slides for a tricord string, and a cross section of the nut that sits astride of the lowest and central slide for a tricord string.I

is a cross section of one of the bass Specification of Letters Patent.

Patented Feb. 26, 1918.

serial No. 852,295.

slides. the nut that sits asti-ide and the Zigzag blocks that will cant the nut to an angle ot G() degrees with the base.

ln Fig. l, A the nietal liraine or string plate, B the treble irres't plate and C the bass iarrest plate. This figure shows Athe location olf the tiro 'w1-est` plates, and the curve in the ln'idge and in the trede plate B. The higl'iest treble string is shown at (L, the lowest treble string at a, the liigliest bicord string at Z). the lowest nnicord st ring at 7), the bass hitch plate is shoii'n at c. the treble hitch plate at c.

In the sound board D, Fig. which lnade tour square, the pert'orations, for the passage of bolts and other appliances. are inadc, as nearly as possible, on. the lines ot the grain of the wood. and a little large in diameter than the bolts and the like, which tra Verse them, so as 'to reduce the r 'finance of the sound board as little as possible and inherent the wood splitting. The three pitch pins fl* ol' each ot each set -that are driven into the treble belly-bridge D are arranged on a line which is parallel with a tangent to Athe curve of the bridge or scale rib ,l at the point Where the center Wire crosses the said rib, so that all Wires in one tricord note shall be exactliv7 the saine length between the rib J and pitch pins d* on the belly-bridge D. The treble belly-bridge shown at D, the bass belly-bridge at D2. The upper part ot the sound hoard D is bent into a. reverse curve toward the rear as shown in 'the edge 'View at Figs. 2 and 3, the curve starting at a point above the belly-bridge and under 'the highest treble strings. The back ribs Z are diminished in depth, Where the reverse carve occurs, as shown at d. The sound board is placed in front of the Wooden frame A, and behind the string plate A to which, and to the Wooden traine, it is secured in an y snitable manner. The sound board is bent backward in a reverse curve in order that adequate space may be provided for the stringing appliances, as may be specially clearly seen by reference. to Fig. 5 of the drawings.

In connection. With the treble, or tricord, Stringing appliances, a curved Wrest plate B, made ot rolled mild steel, is secured to the string' plate A in the opening in the upper4 1 number of separate The way in which the treble wrest plate B is secured to the met-al frame A is shown at Fig. 5.

ln cross section, the wrest plate B is made with two steps, a shallow step B and a deep step B2, each step being set at a downward angle ot' degrees, while the backs are .set at an upward angle et 90 degrees with the steps, as shown in Fig. 5. The edges of the steps malte regular curves struck from a common center, concentric with the bridge J, as shown at B, Fig. l, throughout the treble or tri-cord part or" the piano. rflue baci: or' the plate B is punched with holes 3 in the manner shown at Fig. 10. brass frame E with a bottom plate c, a top plate c and vertical partitions e2, all tenoned together, is laid on the lower step B, thus dividing the step, by the partitions c2, into a compartments, generally about sixty in number, equal to the number of tri-cord notes in a piano. This construction will best be seen in the perspective view, Fig. e. The lfottom plate c oli thc 'frame l, is bolted to the step B by a flat headed rivet The partitions c2 must be radial with the curve olf the edge of the step, c., with the common center. A slide F oblong section but narrower at the back than at the front, is laid on the floor c ot' each compartment; in the top of each slide F is a recess, as shown by the section ot' the slide and the nut in Fig. ll. rilhe slide F does not touch the sides c2 of the compartment with which it is connected. Sitting astride the slide F, is a nut G, the underside oi' which is made with a projection corresponding to the recess in the slide F, so that, if the nut moved in either direction, the slide F will more with it. The nut G makes an easy tit with the internal surfaces oic the compartment; the sides of the nut G are extended so as to embrace the sides of the slide F. A female screw threaded, leithanded, through the center otI the nut G, such female screw being adapted to engage with a male screw H, in the forward end oi which is a square hol iz, to receive the solid end ci a tuning lzey, the arrangement being such that it is the exact opposite of the appliance used to tune an ordinary piano. where a box ley is required to lit over the square heads of the pins. The rear end of the male screw H is provided with a head 71. so that the head le. may be passed through the lower and larger part of one ot the holes Z13, punched in the back part of the wrest plate B, (Fig. l0) and the neck ot the screw then pushed up to the top of the narrow curved part of the hole b3, so that the head L may have a purchase against the back of the plate B. The female screw in the nut will then be engaged with the forward end of the male screw H, the nut will be laid astride of the slide F and the nut screwed up, by turning the male screw H with the tuning hey 2 (Fig. 5), until the wire attached to the end ot the slide F is taut. The slide F has a recess in each side, just behind the extreme forward end or nose f" of the slide, so that the other wires belonging to that trieord note string may pass, one on each side of the center wire, under the nose f', and the proper distance apart of the three wires be maintained. The above description referringr to the slide, the nut, the male and female screws, relates mainly lo what is installed upon the shallow step B' which only carries the appliances connected with the central wire Z of a tri-cord string.

rlhe appliancesconnected with the other wires of a tricord are the same in principle and in all their main features, but vary in detail, owing to the somewhat diiferent conditions under which they operate. Upon the upper and deeper step b2 is laid a trame E similar in all its main features to the 'frame E already describedin connection with the shallow step B. Upon this upper trame F laid another i'rame .F2 similar in all respects to the other trames. The bottom plate of the compartment frame E', will be riveted to the step B2 and the bottom plate ot the frame E2 will be riveted to the top plate ot' the compartment frame E2. The centers of the compartments in the frame E will be a little to the right ot' the centers ot' the compartments in the trame E, and tie centers of the compartments in the trame lll will be a little to the left oft the centers ot the compartments in the frame E, z'. e., the centers ot the compartments in each traine will respectively be exactly in a line with the wires in a tricord string with which that particular frame is associated. Each of the slides F, F F2 (as shown in Figs. S and ll) is of a different shape, owing to the ditlerent positions they occupy. It will be rcmarlred that the top plate c of the frame fll is in the same straight line with the step B2, a', e., it will make part oi the same superticies with the step B2. Each frame E, F/ will be riveted to the step with which it is associated, but, nevertheless, there will be a strong upward pull by the outer wires of the tricord upon the nose 7" ot the slide F, tending to force the top plate e upward. This will be counteraeted by providing each of the upper and outer slides F', F2, with a toe or presser foot f2, f3 so that the pull upward of the outer wires in the tricord upon the nose f of the slide F, shall be counteracted by the downward pressure of the toes f2., f3 upon the plate c.

The rib J is located over the lowest front salient angle of the wrest plate B; all the wires will pass over the rib J downward to the pitch-pins d* on the belly-bridge D, and thence to their respective hitch pins below. The front end slide F will be made of suffilil() cient. length for the nose f to overhang the rib J so that, in the stringing operation, the wires may he readily passed behind the .nose j" without bendingor twisting them. The central wire Z will be passed through au oblique hole under and behind the nose f and hitched to a pin f* above, while the other two wires will pass, in the recesses j', behind the lateral extensions vot the nose f to the front ends ot their respective slides above. All the wires will therefore pass direct from the nose f oli' the slide F over vthe rib il to their respective pitch pins el* on the belly-lnidge D elow, and thence to their respective hitch pins on the string plate The central wire Z which is fastened to the lowest slide will be absolutely independent (so 't'a r as its manipulation is concerned) ot the other two wires with which it is associated to torni one tricord string. It will be hitched to a separate hitch pin i, below on the ring plate. The second wire m and the third wire An, or flank wires are really one continuous wire the upper ends oit which are hitched, one end to the slide F and the other end to the slide F2, thence they pass downward behind the nose j of the slide F. over the ril) J downward to their respective pitch pins d* ou the lielly-bridge D below, then they will torni a loop around a large hitch pin n below the central hitch pin Z. The hitch pin n. should be of a diameter approximately equal to the normal distance between the wires in. and n. The :front edge ot the top plate c2, of the compartment frame l@ will be recessed at intervals so as to permit the tlank wires m, n o'tf the tricord strings to pss freely (without fouling the edge ot the plato c2) from the Vtrent ends ot their reV` spective slides F, F2, direct to the nose otl the slide lll, beneath which they will pass betere they isach the rib il. t is important that cach pin in each set of pitch pins al* should be the same distance from the rib J. This accomplished by arranging the three pins of each set in a row disposed so that a straight line passing through all ot the pins will be parallel to a tangent drawn to the rib .l at the point where the central wire of each set crosses said rib.

The bass strings are some of them bicords and some of them are unicords. Moreover, the bass strings are not set radially from a common center, but parallel to one another, consequently, certain structuii'al modiiications must be made in the bass wrest plate C in order to meet the altered conditions. But, although the construction of the bass wr st plate C is somewhat modified, the principle involved is exactly the same. To the back ot' the frame A, at the bass end (Fig. 7) is secured a rolled steel wrest plate O, with one short step 0 in it. This plate will constitute the backs of both sets of compartw ments, but the upper compartments Will be partly supportedon .the short step. Upon a sheltA near the top .of the ramefA is laid .1nents, while the Zig-zag surfaces above will.

form the bottoms of the upper compartments. A. similar zig-lagged plate will be placed above the upper com partimfnts and will form their tops. Against the sides of the stepped floors will be laid the partitions y) forming the compartments :tor the slides and the nuts. No alterations of importance will be made in the slides, in the nuts or in the screws, these several parts working together in the same *ay as those previously lescril')ed. The arrangement of the punched holes 0 in the back plate O is shown in Fig. 9. The several parts are tightened up and kept together by wedge blocks Q. bolted to the straining plate O behind. Similar wedge blocks K pressing upon a plate K, are applied to the treble wrest plate B, over the top plate of the uppermost comi'iartnient trame E2, (Figs. 4 and 5).

lt will be remarked that whereas the nuts G of the tricords are operated, for timing purposes, at an angle of 45 degrees from below, the nuts oi the bicords and unicords are operated from the same level, 2f. e., horizontally, as may be seen by reference to Figs. 6 and 7.

The several devices hereinbefore described. viz: the large four-square bent sounding benul, 'the appliances for maintaining the wires in one tricord or bicord string at the same length, and the special mode, hereinhe tore rescribed, for Stringing and tuning a pianoforte will combine to produce a fulltoned, true and resonant sound, when any note is struck.

I claiml. ln pianofortes, a string plate having an aperture near the treble corner thereof, the inner edge of such aperture being inclined transversely of its length. at an angle oil degrees and both. the inner and outer edges being curved longitudinally, the curves being struck from a common center located .outwardly thereof, in combination with a rolled metal wrest plate having steps bent to curves struck from the same common center.

2. In upright pianofortes, a string plate having an aperture, a rolled metal wrest plate mounted in the said aperture and being of such a cross section that it is formed into two steps, a shallow and a deep step, the edges of the steps being bent in curves struck from a common center, the top of the wrest plate being Secured to the back of the string plate and the bottom being secured to the front of the latter.

3. In upright pianofortes, the combination with a rolled metal wrestplate provided with steps having their edges bent to curves struck from a common center, of a frame having a top plate and a bottom plate which are bent concentric with the curves of the steps in the wrest plate, and division plates disposed at regular intervals between the top and bottom plates, the said division plates being radial with the said common center, and the top, bottom and division plates being joined to form separate compartments.

l. In upright pianofortes, the combination with a wrestplate provided with steps, the backs of the steps having holes therein, of frames secured to the steps and including bottom plates, slides adapted to slide over the bottom plate of the compartments, nuts straddling the slides and loosely connected therewith so that the slides and nuts may move together, male screws engaged with the female threads ,of the nuts, the said male screws being extended through the holes in the backs of the wrest plate steps and having heads disposed in rear of the said backs to sustain the screws under longitudinal stress, and means provided on each male screw for the accommodation of a tuning key.

5. In pianofortes, Stringing appliances comprising,` in a tricord, three slides, three nuts, one astride of each slide, three female screws, ,one in each nut, three male screws, one engaging each female screw, a keyhole in the front end of each male screw, means at the back of the male screw whereby it may be retained in a fixed position and yet be able to turn when acted upon by a key, and means for securing a wire to the fore end of each slide, as and for the several purposes herein set forth.

6. In upright pianofortes, stringing appliances for a tricerd installation including slides to which the wires are hitched, comprising two side slides and a central slide situated lower than the others, the central and lowest slide having recesses in its opposite sides near the front and terminating in a nose under which the wires from the other two slides pass.

7. In upright pianofortes, Stringing appliances for a tricord installation ineludino', in combination with a wrest plate the top and bot-tom plates of a frame on the wrest plate, three slides, to the front ends of which the wires are hitched, comprising two side slides situated at didercnt heights, and a central slide situated lower than both of the Others, the central and lowest slide terminating at the front end in a nose under which the wires from the other slides pass, the slides being mounted on the bottom plates of separate compartments, a short toc or pressure foot formed on the side slide which is disposed between the remaining slide, and the highest slide having a long toe or presser foot, such toes or presser feet being adapted to press down upon the top plate of the compartment with which the lowest or central slide is associated.

S. In upright pianofortes, the combination of a wrest plate for the bass bicord and unicord strings, frames mounted on the said plate and having their bottoms set at a predetermined angle, slides movable on the bottoms, and means for adjusting the slides.

CARL CHRISTIAN MEINZOLT.

Titnesses A. Massey, II. C. CAMPBELL.

Copies of this patent may be obtained for ve cents each, by addressing the Commissioner of Patents, Washington, D. C. 

